OBJECTIVE: This study compared the severity of depression in preschoolers diagnosed by standard versus modified DSM-IV criteria for major depression. METHOD: A group of 145 preschoolers and their caregivers underwent a diagnostic assessment for preschool children. A factor analysis of depressive symptoms from the group was performed to derive a depression severity score. Scores were compared among four groups: standard DSM-IV major depression, modified DSM-IV major depression, DSM-IV attention deficit hyperactivity disorder and/or oppositional defiant disorder, and no disorder. RESULTS: A hierarchy in severity emerged, with significant differences among all four groups. Preschoolers meeting standard criteria displayed the highest severity, followed by those who met modified criteria. Both depressed groups had significantly higher severity than the two comparison groups. CONCLUSIONS: Standard DSM-IV criteria captured the most severely affected preschoolers, missing a substantial proportion of children with potentially clinically significant but less severe symptoms who were captured by modified DSM-IV criteria.